Enhanced channel estimation technique in MIMO-OFDM system

Author(s):  
M. A. Ahmed ◽  
S. A. Jimaa ◽  
I.Y. Abualhaol
Author(s):  
Musayyanah . ◽  
Yoedy Moegiharto ◽  
I Gede Puja Astawa

Multicarrier modulation technique as Orthogonal Frequency Division Multiplexing (OFDM) is able to vanishIntersymbol Interferences (ISI) caused by multipathchannel. Merging with multi- antenna transmission techniques such asMIMO become MIMO- OFDM system is able to improve (data rate transmission)the transmission of data and capacity of the system. Pilot channel estimation technique with the algorithm Linear Minimum Mean Square Error (LMMSE) with modulation m-PSK is applied in this study. The results obtained in the form of graphs BER against EbNo which shows that the system performance with LMMSEestimator has a different gain for QPSKmodulation better about 0.75 dB, for 8 PSKmodulation is about 1.5 dB and for 16 PSKmodulation around 1 dB compare to LS estimator. Number of the largest antenna both in the transmitter and receiver produce the best system performance. Observation for QPSKmodulation shows a scheme transmitter- receiver antenna 4x2 having gain approximately 9 dB better than the number of the lowest transmitter antenna(1x2). For scheme 4x4 shows gain around 8,5 dB than the number of the lowest receiver antenna.Keywords:MIMO, OFDM,LS, LMMSE, MPSK.


2014 ◽  
Vol 14 (2) ◽  
pp. 97-102
Author(s):  
SR Aryal ◽  
H Dhungana

There are no limit of human desire, so day by day we need much higher data speed to facilitate our need but every physical resource like frequency band, transmit signal strength are finite. Within the given limited resource, higher data speed is accomplished by new proficiency called Multiple Input Multiple Output (MIMO), Orthogonal Frequency Division Multiplexing (OFDM) system. MIMO-OFDM fulfills the high data rate requirement through spatial multiplexing gain and improved link reliability due to antenna diversity gain. With this technique, both interference reduction and maximum diversity gain are achieved by increasing number of antennae on either side. Received signal in MIMO-OFDM system is usually distorted by multipath fading. In order to recover the transmitted signal correctly, channel effect must be estimated and repaired at receiver. In this paper the performance evaluating parameter mean square error and symbol error rate of least square error, minimum mean square error and DFT based channel estimation methods are estimated and appropriate solution is recommended. Furthermore, comparison among their characteristics is simulated in MATLAB and useful conclusion is delineated. DOI: http://dx.doi.org/10.3126/njst.v14i2.10421   Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 97-102


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